The 2nd installment to the Darker than Black series. This follows Suo after her house has caught fire and she crosses paths with the previous protagonist Hei. He is searching for a lost friend and takes pity upon Suo and allows her to tag along with him. Together they start to unveil Suo's past and her relationship with her family. As they dig deeper, they discover that somehow what Hei was searching for ties in with Suo. They soon learn a dark secret that changes everything.
In Tokyo, an impenetrable field known as "Hell's Gate" appeared ten years ago. At the same time, psychics who wield paranormal powers at the cost of their conscience also emerged. Hei is one of the most powerful of these psychic agents, and along with his blind associate, Yin, works for one of the many rival agencies vying to unlock the mysteries of Hell's Gate.
This series is set a couple of years after the original; if you want to know what happened between the two series you need to watch the four OVA episodes; strangely these are on disc three of the 'Season Two' box set, at least they are here in the UK. The series starts in Russia where thirteen year old Suo lives with her father and twin brother Shion until one day their house is attacked. She assumes they have been killed in the attack and heads to Japan hoping to find her mother. She is accompanied by Hei, who has been badly affected by the loss of Yin, Mao who is now a flying squirrel and a doll called July. It turns out that Suo is a contractor; she can create an antitank rifle out of thin air! There are several contractors after her including one of her school friends who has the power to summon enough insects to kill a person or even derail a train! While Suo wants to find her mother Hei is keen to find Yin again; the problem is many people want to stop him believing a prophecy that suggests if they meet again it could be the end for all contractors.

While this series is quite different to the first I enjoyed it just as much; Suo makes a good protagonist and the season contains one long story arc rather than relying on several three or four part stories. While only a few original characters return it is good to see Hei, policewoman Misaki Kirihara, although she is now working for the shadowy 'Section Three, and Mao return. Over the course of the series Suo's character develops nicely and that development includes a couple of real surprises that I won't spoil here.

These comments are based on watching the series in Japanese with English subtitles.
Starting with some seemed separated stories but turn out to be a piece in the chain. The story line of contractor is really extraordinary when it deals with the basic problem of humanity, the equality and rationality of human race. Everything has a price indeed, and would we be able to sacrifice some people for the sake of all others, that is the true fact, and conclude with the most benevolent decision from the people who is thought to be a devil.

I have never watched such a good series before, to the point that I have to go up here and write a review about it. So excellent that it leaves me the sad feeling for months to go. Wonderful. I truly hope to see it again for a season 3 or something like that

The music, people might think it is not so good but in fact contain the main philosophy of the whole anime that we need to watch until the very end to understand its true meaning, really momentum at first when I got the idea behind.